Shielded structure for radiation treatment equipment and method of assembly

ABSTRACT

A modularized approach for rapidly and cost effectively assembling a structure suitable for housing radiation emitting equipment is disclosed. The modules include reinforced walls to contain radiation shielding fill material. The modules are transported empty and then filled on site with the fill material to form a radiation shielding barrier around radiation emitting equipment.

RELATED APPLICATION DATA

This application is a continuation of U.S. application Ser. No.09/854,970 filed May, 14, 2001, now U.S. Pat. No. 6,973,758, thedisclosure of which is hereby incorporated by reference.

BACKGROUND

The present invention relates generally to structures and portionsthereof for housing radiation emitting equipment and shielding humansworking near the equipment. More particularly but not exclusively thepresent invention relates to a modularized approach for rapidly and costeffectively assembling a structure suitable for housing radiationemitting equipment. In a preferred embodiment, the structure may be usedin medical applications.

Radiation is used in the diagnosis and treatment of patients in variousways. However, while controlled doses can be beneficial to a patient,those working with the radiation or merely in the surrounding area needto be protected from the harmful effects of the radiation. Accordingly,shielding is traditionally provided to isolate the radiation source fromthose in the surrounding area and provide some protection from thelevels associated with normal use of the equipment and also, to someextent, to accidents with the radiation equipment.

However, the need for shielding, which is traditionally provided byconcrete walls or mounds of dirt, severely limits the feasibility ofradiation treatment centers in many locations. This limitation is due atleast in part to the high cost of constructing these buildings and tothe inability to easily disassemble or remodel the centers toaccommodate new development of the surrounding structures and land.Accordingly, new apparata and techniques are needed for rapidly andeconomically constructing radiation treatment centers to allowfacilities to be located wherever patients needs require suchfacilities. Various embodiments of the present invention address theseand other needs.

SUMMARY

The present invention provides systems and techniques for rapidly andcost effectively assembling structures for radiation emitting equipment.While the actual nature of the invention covered herein can only bedetermined with reference to the claims appended hereto, certain aspectsof the invention that are characteristic of the embodiments disclosedherein are described briefly as follows.

In one aspect, a system for housing radiation emitting equipmentcomprises: a plurality of modules that are connected to form an interiorarea and a barrier substantially surrounding the interior area. Theinterior area is adapted for human occupation and to contain radiationemitting equipment, and the modules comprise a support frame structureand at least one wall, wherein the support frame structure ishorizontally elongated and permits the module to be free standing. Thebarrier includes first and second spaced apart rigid walls and aquantity of radiation shielding filler material contained between thefirst and second walls. The quantity of filler material is sufficient tosubstantially reduce the measurable radiation level outside the interiorarea when radiation is emitted from the radiation emitting equipment. Inone refinement of this system at least two of the plurality of moduleseach include portions of said first and second spaced apart rigid walls,the portions defining a channel comprising a portion of the barrier. Inanother refinement, radiation shielding plates are mounted to thesupport frame structure at selected locations to provide additionalradiation shielding. In a still further refinement, a second pluralityof modules are connected to form a roof over the interior area, the roofincluding a roof barrier above the interior area comprising a rigidfloor supporting a quantity of radiation shielding filler material abovethe interior area. In another refinement, the interior area comprises aportion of at least one module that includes a frame structure forsupporting the radiation emitting equipment.

In another aspect, a method of constructing a structure for housingradiation emitting equipment comprises: transporting a plurality ofmodules to a site; positioning the modules adjacent each other with amajor axis of each module horizontal; connecting adjacent modules;forming a channel spanning adjacent modules; pouring radiation shieldingfiller material into the channel to form a barrier; and providingradiation emitting equipment in a central area bordered by the barrier;wherein the quantity of filler material is sufficient to substantiallyreduce the measurable level of radiation outside the central area whenradiation is emitted by the equipment in the central area. In onerefinement, the modules each have a long side and a short side andconnecting adjacent modules involves connecting their long sidestogether. In another refinement, a floor structure is formed over thecentral area; and radiation shielding filler material is poured onto thefloor structure.

In another aspect, a method for constructing a structure housingradiation emitting equipment comprises: providing a piece of radiationemitting equipment; providing a free standing frame structure;supporting spaced apart rigid walls with the frame structure to form achannel open at the bottom of the frame structure and laterally spacedfrom the radiation emitting equipment; and pouring a sufficient amountof a granular fill material into the channel to form a radiation barrierto protect persons on one side of the barrier from the harmful effectsof the radiation emitted by the radiation emitting equipment on theother side of the barrier. In one refinement, a plurality of freestanding frame structures are provided and the channel spans betweenframe structures. In another refinement, a support frame structure isprovided attached to the free standing frame structure; and theradiation emitting equipment is supported on the support framestructure. In a still further refinement, a direction is selectedrelative to the radiation emitting equipment; and radiation shieldingplates are attached to the free standing frame structure to provideadditional shielding in the selected direction.

In another aspect, a method comprises: providing a transportable modulefor forming a structure, the module comprising: a free standing framestructure, a pair of spaced apart reinforced rigid walls mounted to theframe and defining a channel space between the walls, wherein at least aportion of the channel space between the walls does not contain aceiling or a floor, lifting the module by its ends; placing the moduleon a foundation with a major axis of the module horizontal; and fillingthe channel space with a radiation shielding granular fill, the granularfill contacting the foundation to form a substantially continuouslateral barrier to protect persons on a first side of the channel spacefrom radiation emitted by a piece of radiation emitting equipment on asecond opposing side of the channel space. In one refinement, lateralforces acting from inside the channel to force the walls apart areresisted with rigid supports connected in the channel space between thewalls. In another refinement, a piece of therapeutic radiation emittingequipment is provided on the second side of the channel space, and ahuman on the second side is subjected to therapeutic radiation doseswith the therapeutic radiation emitting equipment. In a still furtherrefinement, a plurality of modules are provided.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an assembled modular structure accordingto one embodiment of the present invention.

FIG. 2 is an exploded, perspective view in partial section of themodular structure of FIG. 1.

FIG. 3 is a top plan view of the first floor level of the structure ofFIG. 1.

FIG. 4 is a top plan view of the second floor level of the structure ofFIG. 1.

FIG. 5 is a top plan view of a first pod in the embodiment of FIGS. 3and 4.

FIG. 5A is a side elevational view in full section of the FIG. 5 pod.

FIG. 5B is a partial enlarged top plan view in full section of adjacentwall segments and a wall support.

FIG. 6 is a top plan view of a second pod from the embodiment of FIGS. 3and 4.

FIG. 6A is a side elevational view in full section of the FIG. 6 pod.

FIG. 6B is a top plan view in full section of the FIG. 6 pod.

FIG. 7 is a side elevational view in full section of a third pod fromthe embodiment of FIGS. 3 and 4.

FIG. 8 is a top plan view of a sixth, second floor pod from FIG. 4.

FIG. 8A is a side elevational view in full section of the FIG. 8 pod.

FIG. 8B is an end elevational view in full section of the FIG. 8 pod.

FIG. 9 is a top plan view of a ninth, second floor pod.

FIG. 9A is an end elevational view in full section of the FIG. 9 pod.

FIG. 10 is a top plan view in full section of an alternative arrangementfor a third pod in the embodiment of FIGS. 3 and 4.

FIG. 11 is a side elevational view in full section of the FIG. 10 pod.

FIG. 12 is a top plan view of an alternative arrangement for a ninth,roof pod in the embodiments of FIGS. 3 and 4.

FIG. 13 is a side elevational view in full section of the FIG. 12 pod.

FIG. 14 is a front elevational view of the lifting mechanism for theretractable threshold.

FIG. 14A is a side elevational view in full section of the threshold ofFIG. 14 in the raised position adjacent the closed vault door.

FIG. 15A is an end elevational view in partial section of arepresentative connection between the lower rails forming the long sidesof adjacent pods.

FIG. 15B is a top plan view in partial section of a representationconnection between the corner posts of adjacent pods.

FIG. 15C is a top plan view in partial section of a representativeconnection between interior wall segments of adjacent pods.

FIG. 15D is an end elevational view in partial section of an upper railconnection between adjacent pods.

FIG. 15E is a top plan view in partial section of an adjacent podconnection to a door gusset portion of a pod.

FIG. 15F is a side elevational view in partial section of arepresentative connection between an end of a roof pod with the outerwall and frame of a footprint pod.

FIG. 15G is a side elevational view in partial section of arepresentative ion of the load support beams in the roof pods with theroof support structures in print pods.

DESCRIPTION OF THE PREFERRED EMBODIMENT

For the purposes of promoting an understanding of the principles of theinvention, reference will now be made to the embodiment illustrated inthe drawings and specific language will be used to describe the same. Itwill nevertheless be understood that no limitation of the scope of theinvention is thereby intended, such alterations and furthermodifications in the illustrated structures and methods, and suchfurther applications of the principles of the invention as illustratedtherein being contemplated as would normally occur to one skilled in theart to which the invention relates.

Turning now to FIGS. 1 and 2, structure 40 for housing therapeuticradiation equipment is depicted. Structure 40 is a modular unit that isassembled to form a radiation therapy vault room 50, and can bedelivered to a site in sections with all equipment and finishings inplace. The individual sections 101-110, herein referred to as pods ormodules, are preferably each capable of being shipped by rail, ship, oroverland freight and of being assembled together using commonlyavailable equipment such as cranes or container movers. In addition, thepods are preferably built to meet the US Department of Transportation(DOT) regulations concerning travel on the interstate highways.Currently, the DOT code includes a weight limitation of 85,000 poundsincluding the tractor and the trailer along with size limitations of awidth not exceeding 14 feet, a height not exceeding 13 feet 6 inches,and a length not exceeding 53 feet.

Referring now to FIGS. 1-4, as assembled, the modular structure 40includes a total of ten pods and has two or more interior rooms. Oneroom 50 is adapted to contain equipment capable of being used to performradiation therapy, and the other room 60 is adapted to be used as acontrol area suitable for use by a radiation therapist operating theequipment contained in room 50. Either room 50 and/or room 60 can befurther divided into additional rooms, for example to provide a patientwaiting area or multiple treatment areas. The modular unit 40 also has aseries of interior and adjoining containers that can be filled withradiation shield material to form a barrier 70 around the treatment area50 and a roof barrier 80 above the treatment area 50. The radiationshield material can be a flowable and/or granular material such as sand.

Five pods (pods 101-105 referred to as the footprint pods) are used toform the footprint of the building 40 (see FIG. 3). An additional fivepods, (pods 106-110, referred to as the roof pods) are placed on top ofand perpendicular to the five footprint pods (see FIG. 4). Of the fiveroof pods, four pods (pods 106-109, referred to as the “roof shieldingpods”) give additional radiation shielding in the vertical direction byway of the roof barrier 80, whereas pod 110 is primarily used as astorage area.

Pods 102, 103, and 104 connect together to form the interior workspaceor therapy room 50. These pods align to form a continuous unobstructedspace, for example a space measuring approximately 24 feet wide and 20feet in length. Pod 103 serves as the center footprint pod, containingmost of the medical equipment, and has quick connections for electricalpower and a mounting platform for the medical equipment 600. A weatherseal can be incorporated along the joints between all of the footprintpods as well.

Pod 101 is attached to the exterior side of pod 102, and pod 105 isattached to the exterior side of pod 104. These two pods (pod 101 andpod 105), together with portions of pods 102-104, receive the radiationshielding material to form the barrier 70. The barrier 70 extendssubstantially around all sides of the room 50, with pod 102 including adoorway to permit access to the treatment room 50. The roof shieldingpods (pods 106-109) are placed above and connected to the five footprintpods, at least pods 101 and 105 including roof support structures 120,122 to support the load of the roof pods. Pods 106-109 are used forradiation shielding purposes whereas pod 110 can be reserved to housethe electrical equipment, telephone equipment and other utilities.

For assembly a suitable foundation, such as a concrete slab, is firstcreated. The foundation is then leveled and the first of the footprintpods, for example pod 103, is placed on and anchored to the foundation.The remaining footprint pods are then sequentially placed and attachedto their respective adjoining pod(s) and to the foundation and a weatherseal is formed between adjoining pods and the foundation. A portion ofthe radiation shielding material can then be pumped into the containersof the various footprint pods to form the barrier 70.

Either before or after filling the containers of the various footprintpods with the radiation shielding material, the roof pods can be placedon and attached to the five footprint pods. A weather seal can then bemade between the footprint pods and the roof pods as well as betweenadjoining roof pods. The modular structure 40 can then be filled withthe shielding material. Electrical, water and sewage are then connectedto the modular unit. By providing the structure 40 as a modular unit,the assembly time from the pods' arrival on site to the finishedstructure 40 can be minimized. It is envisioned that the formation ofthe structure 40 would only take on the order of a few (3-4) days,greatly decreasing the time and cost traditionally needed to construct aradiation treatment facility.

Having described the general layout of the pods and the formation of thestructure, more particular features of the individual pods areconsidered. Each of the pods can be built with an outside dimensiongenerally the same as a standard eight by forty foot extended height(9′6″) shipping container. The pods are transportable, which means thatthey each meet DOT regulations and codes for overland freight.Optionally, each can also be rigidly constructed to be capable of beinglifted from the end points by a container mover. They can also be formedto be stacked five pods high, for example during transit in an oceangoing vessel. The pods can also be constructed to be shipped and stackedwith other container types where the other containers having a grossweight of 96,000 pounds each. The shipping weight of each pod, includingany additional shielding or support structures or other integratedcomponents, but without the radiation shielding fill material, is mostpreferably consistent with DOT shipping regulations for moving by truckwithout special permitting.

More particularly, each of the pods is constructed of a steel exteriorskeleton or frame 90 (see FIG. 5) that generally defines the outer edgesof the pod. The frame 90 is preferably formed of square channel and flatplate steel welded, bolted, or otherwise securely fastened together toform the boundaries of the generally rectangular solid shape of the pod.“C” shaped beams 92 form the longer lower sides of the rectangularfootprint of each pod, with angled rails 96 forming the upper borders.Rectangular posts 94 form the four side edges between the upper 96 andlower 92 rails. Where present, wall segments are secured to the interiorof the skeleton or frame 90 (for example by welds or rivets) with anywall or floor segments intended to contain the radiation fill materialformed of flat sheet steel. Other wall, floor, or ceiling segments canbe mounted to the frame and formed of any suitable building material.Where, a wall, floor, or ceiling segment is not present in anyindividual pod, or is of non-load bearing construction, structuralrigidity of the pod can be increased to the desired level by providingrigid support members between segments of frame 90.

Turning now to FIG. 5, pod 101 is constructed in two regions, a fillarea 210 and a finishable area 212. The fill area 210 forms a part ofthe barrier 70 and does not contain a floor so that the radiationshielding material provided into area 210 can be substantiallycontinuous to the foundation. Area 210 also does not have a ceiling. Thefinishable area 212 has no side wall along the section that joins to pod102, but a floor can be provided. The interior of area 212 can besuitable for interior finishing of the floors, wall and ceiling to makeit a patient area.

Fill area 210 is defined by oppositely disposed vertical inside andoutside walls 214 and 216 and side walls 215 and 217. Optionally, insidewall 216 is at least partially absent at the portion that adjoins to thebarrier regions of pod 102 to permit fill material to flow between theadjacent barrier regions. Each of the walls are rigid and can bereinforced to contain the load of the radiation fill material withoutsubstantial deflection. Each of the walls are constructed of flat panelsteel and have a plurality of vertically oriented supports 202 welded orotherwise affixed thereto at spaced intervals along the wall length.Where more than one wall panel 510 is required to span the length of awall, the supports 202 also serve to connect adjacent panels of the wallmaterial. (See FIG. 5B) The supports are elongated pieces with a “L”shaped cross section having one flat portion 202 b welded or riveted toadjacent steel wall sections 510 and a second flat portion 202 agenerally perpendicular to the wall panels 510. The perpendicularextending portions of supports 202 are tapered such that they arethicker at the bottom of the walls where the largest lateral force fromthe fill material can be expected. (See FIG. 5A)

For additional lateral support in the radiation fill area, rigidhorizontal supports 204 are also affixed generally between the topportions (204 a in FIG. 5A) and bottom portions (204 b) of the walls, orequivalently directly to the frame structure 90. Steel supports 204extend between walls 216 and 214 and at angles between wall 215 andwalls 216 and 214 and between wall 217 and walls 214 and 216.

In typical use the lateral force on the walls of container 210 could be170,000 pounds at a pressure of approximately 6.4 pounds per squareinch. The maximum lateral force could be increased by the weight of thefill from the roof pods on the top of pod 101, and the wall material,thickness and supports should be chosen to support the load.

It is to be understood that the actual load and pressures experienced bythe various portions of the pods might vary by a factor of 10 or more ineither direction from any of the estimated loads presented herein. Amongother things, these exemplary loads can be expected to depend on thedensity of the fill material. In addition, the walls and/or associatedsupports can be designed to withstand several times the expected loadfor any particular application.

In addition, access ports can be placed at appropriate intervals alongthe walls of container 210 to allow a pump or other suitable fillmechanism to fill and empty the container of the shielding material.Alternatively the fill portion 210 can be filled and emptied through itsopen top and bottom.

Pod 101 is constructed to include central region 218 in which additionalshielding, such as a lead plate, may be added. Region 218 can be, forexample, eight feet wide by 9.5 feet high and seven inches thick andlocated near the center of pod 101 or wherever relatively largerradiation levels could be expected (for example depending on theorientation and use of the medical device in room 50). A variety ofshielding materials may be used for this purpose and they may be apassive or a structural part of the pod. Diagonally extending rigidlateral supports 219 are provided to accommodate any additional weightof the additional shielding material.

The roof shielding pods will be placed on top of pod 101 perpendicularto the footprint pods and filled with radiation shielding material. Theweight of the filled roof shielding pods could be as high as 250,000pounds each, all of which load can be substantially supported by pod 101and pod 105. Pod 101 includes roof supports 120 as a portion of the wallto hold one half of the weight of the four roof shielding pods andtransfer the weight to the foundation below. As discussed above, themajority of portion 210, like similar fill areas of the other footprintpods, has an open top to allow fluid communication with the roof pods.

Turning now to FIG. 6 and with continued reference to FIGS. 3 and 4, pod102 is adjacent to pod 101. Pod 102 also has several regions within it.Region 220 is eight feet wide by six feet deep and the full height ofthe pod. It is located in the rear of the pod and forms a portion of thebarrier 70. When filled with radiation shielding material the weight ofthe fill in portion 220 might be 44,0000 pounds with approximately 6.4pounds per square inch of weight. Area 220 does not contain a floor orceiling so that the shielding material can be substantially continuousto the foundation and to the roof barrier. The lateral force on the sidewalls might be 34,000 pounds, and the maximum lateral force could beincreased by the weight of the fill from the roof shielding pods on thetop of this pod. The wall material, thickness and supports should bechosen to support these exemplary loads or the load for any particularapplication.

Area 221 contains a vault door 130. Door 130 is five feet wide by sevenand one half feet high. The door is a hollow steel door eight inchesthick. The hollow portion of the door can be filled with four inches oflead, and 3.8 inches of boridated polyethylene. It is envisioned thatthe weight of the door with its frame and additional wall shieldingadjacent to the frame will be approximately 10,000 pounds.

Door 130 is located between areas 221 a and 221 b that, like area 220,are adapted to receive the radiation fill material. Door 130 separatesthe control room 60, or patient area 65 (of which area 222 is a part)from the treatment room 50 allowing access back and forth. Area 222 alsoincludes a standard exterior door consistent with local building codesto allow access to the patient area 65.

Portions 223 and 222 are suitable for interior finishing of the floors,walls and ceiling to make it a patient area. They can also haveprovision for a quick connect for electricity, for lighting and tooperate the vault door 130.

Pod 102 also includes a door jam mechanism to be used for additionalprotection against radiation out leakage in the event there is no mazeshielding walls (as is traditionally provided at the entrance toradiation rooms) or when the maze is not sufficient to adequately blockradiation leakage. The mechanism includes a lifting mechanism coupled toa retractable threshold 132 that pops up to be adjacent to door 130 uponthe closing of the vault door 130, effectively blocking radiationleakage. The threshold 132 retracts, returning to its place upon theopening of the door. The lifting mechanism can include a pair ofhydraulic cylinders 134, 136 (see FIGS. 14 and 14A) of the type known aspancake cylinders. A gear or lever assembly actuatable under the forceof the closing door could also be used. The lifting mechanism (cylinders134, 136) are electronically or hydraulically activated by a switch thatsenses whether the door is open or closed, for example by provision of apair of cooperating magnetic sensors mounted on the door and door jamrespectively. Preferably the threshold 132 is electronically interlockedwith a pair of door switches and/or with the radiation machine 600 suchthat the machine 600 is prohibited from being in use when the door 130or the threshold 132 are in a position to allow radiation leakage fromthe room.

The door jam is normally hidden and level with the floor so as not to bea hazard for persons walking across it. When the vault door 130 isclosed, cylinders 134, 136 raise the threshold above the bottom of thedoor to block radiation leakage under the door. In the event of anyemergency, the pop-up mechanism of the door jam can work in conjunctionwith the vault door and/or be actuated manually. For example, the doorjam can require electrical power to stay in the raised position suchthat in the event of a power failure, the threshold 132 automaticallyretracts under its own weight. The door jam is an enhancement to anyradiation therapy center, as most centers do not utilize any type of aseal under a vault door. The door jam is not restricted to the use ofthe modular system and can be retrofitted to any type of door as wouldoccur to those of skill in the art when presented with the presentdisclosure.

Pod 103 is located in between pod 102 and pod 104. It is to be builtwith an outside dimension the same as an eight by forty-foot extendedheight (9′6″) shipping container. When finished, it can meet DOTregulations and codes and be capable of being lifted from the end pointsby a container mover.

As illustrated in FIG. 7, pod 103 is divided into four sections.Sections 302 and 306 are fill areas that do not contain a ceiling or afloor and are open to the fill areas of the adjacent pods. The lateralforce on the side walls might be 34,000 pounds, where the maximumlateral force could be increased by the weight of the fill from the roofshielding pods on the top of this pod. The wall material, thickness andsupports should be chosen to support this exemplary load or the loaddictated by any particular application. Access ports can be placed atappropriate intervals to allow a vacuum pump to fill and empty thecontainer of the shielding material.

Additional shielding panels 303 and 305 are added between areas 302 and304 and between areas 304 and 306. Steel may be used for this purpose,and it may be a passive or a structural part of the pod.

There is no side wall on areas 304 and 308 adjacent to pods 102 or 104.Pod 103 is capable of being connected to pods 102 and 104 with awatertight weather seal and it has provisions to anchor it to thefoundation in accordance with standard building codes for a mobilebuilding. Areas 304 and 308 are suitable for interior finishing of thefloors, walls and ceiling to make it a patient area.

Pod 103 is adapted to hold a medical treatment device, such as onecontaining a therapeutic radiation source. There are severalmanufacturers of such equipment, and the design of the structure and pod103 in particular will be as universal as is economically possible toallow for the incorporation of as many different makes and models of thetreatment device as possible. In general, the average machine weighs18,000 pounds and bolts to a base plate such as base plate 310. Thebolts that hold the machine are at one end of the machine and the bulkof the weight is at the other some ten feet forward of the boltsyielding a significant moment of torque. A steel base frame isincorporated into the steel frame of pod 103 to accommodate this torque.The frame is sufficiently rigid such that regardless of any bending ortwisting during transit, when the frame of pod 103 is placed on aprecision leveled foundation, the machine will be level to within themanufacturers specifications. Other electrical equipment including acontrol console, modulator rack, power transformers, and power filterscan also be mounted within pod 103. Wiring conduits are built into theframe to service the electrical equipment.

Pod 104 is substantially a mirror image of pod 102 with a few minorexceptions. Pod 104 fits in between pods 103 and 105, and does notinclude a vault door. In addition, whereas portion 222 of pod 102included an exterior door, the equivalent portion of pod 104 can includeother amenities such as plumbing for a wash basin.

Pod 105 is substantially a mirror image of pod 101 although it iscontemplated that the equivalent portion to portion 212 of pod 101 willbe adapted for a different purpose, such as storage, restrooms, etc.

With reference to FIGS. 8 and 8B, pod 106 is one of four roof shieldingcontainers to be placed on top of and perpendicular to footprint pods101 through 105. Each of the roof shielding containers can be built withan outside dimension the same as a standard shipping container. Pod 106is placed at the rear of the modular unit. The bottom of pod 106attaches to the top of the footprint pods 101 through 105. The side ofpod 106 that attaches to pod 107 does not have a wall, but it includes acentral rigid support between the upper and lower frame segments. Whenfinished it can meet DOT regulations and codes, and be capable of beinglifted from the end points by a container mover. It can also be capableof being stacked five containers high with the other containers having agross weight of 96,000 pounds each and be capable of being shipped witha gross weight of 96,000 pounds. The shipping weight of the pod with theadditional shielding and the roof support structures but without theradiation shielding fill material is preferably consistent with DOTshipping regulation for moving by truck without special permitting.

As is the case for all of the roof pods, there is no floor in pod 106 inthe area over pod 101 and pod 105 and over the shielding containers inpods 102, 103 and 104 although there is a steel floor over the treatmentroom portions of the footprint pods. In addition, there is a ceiling orroof covering all of pod 106 (as is also the case for all the roofpods). When filled with radiation shielding material the total weight ofthe fill could be 243,200 pounds with approximately 5.3 pounds persquare inch of weight on both the shielding in the lower pods and on thefloor in the existing areas of this pod. The lateral force on the sidewalls could be 115,520 pounds. The lateral force could be approximately5.3 pounds per square inch occurring near the bottom of the pod. Thewall material and thickness and supports should chosen to support thisexemplary load or any particular load depending on the application.Access ports can be placed at appropriate intervals to allow a vacuumpump to fill and empty the container of the shielding material. Inparticular, access ports 325 can be provided along the roof as a seriesof spaced apart holes with normally closed spring loaded covering flapsthrough which access to the interior space of the roof pods can beselectively provided.

Pod 106 is supported by the four steel supports 120 in pods 101 and 105.It is constructed to span pods 102, 103 and 104 without bowing orplacing any undue stress on these three pods, and includes a pair ofI-beams 320, 321 to distribute the load on the steel floor to supports120.

Pod 107 is another of four roof shielding containers to be placed on topof and perpendicular to the footprint pods 101 through 105. It is placedin front of and adjacent to pod 106 at the rear of the modular unit. Thebottom of pod 107 attaches to the top of footprint pods 101 through 105.The side of pod 107 that attaches to pod 108 also does not have a wall,which helps to minimize gaps and/or radiation leaks through the roof.Pod 107 attaches to the five footprint pods and to pod 106 and 108.There will be no floor in pod 107 in the area over pod 101 and pod 105.When filled with radiation shielding material the total weight of thefill could be 243,200 pounds with approximately 5.3 pounds per squareinch of weight on both the shielding in the lower pods and on the floorin the existing areas of this pod. The lateral force on the side wallscould be approximately 115,520 pounds. The wall material and thicknessand supports should be chosen to support this exemplary load or theparticular load as determined by the application. Access ports areplaced at appropriate intervals to allow a vacuum pump to fill and emptythe container of the shielding material.

Pod 107 is supported by the supports 120 in pods 101 and 105. It is beconstructed to span pods 102, 103 and 104 without bowing or placing anyundue stress on these three pods, and includes four I-beams to span pods102 though 104 and distribute the load to the supports 120.

Pod 108 is one of four roof shielding containers to be placed on top ofand perpendicular to the footprint pods 101 through 105. It is placed infront of and adjacent to pod 107 near the center of the modular unit.The bottom of pod 108 will attach to the top of footprint pods 101through 105. One side of pod 108 will attach to pod 107 and the otherside will attach to pod 109. There is no floor in pod 108 in the areaover pod 101 and pod 105. When filled with radiation shielding materialthe total weight of the fill could be 243,200 pounds with approximately5.3 pounds per square inch of weight on both the shielding in the lowerpods and on the floor in the existing areas of this pod. The lateralforce on the side walls could be 115,520 pounds. As discussed above withrespect to the other pods, the wall material and thickness and supportsshould be chosen to support this exemplary load. Access ports can alsobe placed at appropriate intervals to allow a vacuum pump to fill andempty the container of the shielding material.

Pod 108 is supported by the supports 120 in pods 101 and 105. It is beconstructed to span pods 102, 103 and 104 without bowing or placing anyundue stress on these three pods, and includes four I-beams to span pods102 though 104 and distribute the load to the supports 120.

With reference to FIGS. 9 and 9A, pod 109 is one of four roof shieldingcontainers to be placed on top of and perpendicular to the footprintpods 101 through 105. It will be placed in front of and adjacent to pod108 near the center of the unit. The bottom 505 of pod 109 will attachto the top of footprint pods 101 through 105. There is no floor in pod109 in the area over pod 101 and pod 105 and over the shieldingcontainers in pods 102, 103 and 104. When filled with radiationshielding material the total weight of the fill could be 243,200 poundswith approximately 5.3 pounds per square inch of weight on both theshielding in the lower pods and on the floor in the existing areas ofthis pod. The lateral force on the side walls could be 115,520 pounds.As described above with respect to the other pods, the wall material andthickness and supports should be chosen to support this exemplary load.Access ports can also be placed at appropriate intervals to allow avacuum pump to fill and empty the container of the shielding material.

Pod 109 is supported by the supports 120 in pods 101 and 105. It is beconstructed to span pods 102, 103 and 104 without bowing or placing anyundue stress on these three pods, and includes I-beams 520, 521 to spanpods 102 though 104 and distribute the load to the supports 120.

Pod 110 is a utility area that will be one of the five roof pods. Pod110 will be placed on top of and perpendicular to pods 101 through 105.Pod 110 will have several rooms built into it. These rooms will be forutility areas and will be built to be consistent with local buildingcodes for electrical, telephone, plumbing and other utilities asrequired.

It is envisioned that pod 110 could also be supported by supports placedin pods 101 and 105. However, it is envisioned that since pod 110 wouldnot contain the radiation fill material, the load of pod 110 would besubstantially less than the load of any of pods 106 through 109 and thuscan be supported in any conventional fashion.

In one variation of the modular structure the medical device can beremoved and replaced after the structure is completed in a simple andefficient manner. This variation involves modifications to pods 103 and109 such that the portion of pod 103 containing the medical device andany associated control system can be removed and replaced while theremainder of the structure and the majority of the radiation fillmaterial remains in place.

Turning now to FIGS. 10 and 11, pod 103 a, which is a modified versionof pod 103, is depicted. Pod 103 a includes radiation fill section 402that is separated from the radiation treatment room 50 by lead shield403. The removable portion of pod 103 a includes the treatment roomportion 404, barrier portion 420 and control room portion 406. Thetreatment room portion 404 includes the base plate that would be coupledto the medical device and is removable with respect to treatment roomportions 410 and 408. The control room portion 406 includes theassociated control equipment and electronics and is electrically coupledto and integral with portions 420 and 404.

The barrier comprising portions 416, 418 and 420 in pod 103 a can befilled with radiation shielding fill material. Portions 416 and 418 arerelatively fixed and would normally remain filled with shieldingmaterial even during the medical device interchange operation. Thecenter barrier portion 420 is part of the removable section of pod 103 aand can be evacuated of its radiation fill material as necessary toremove and replace the medical device. The walls of radiation fillportions 416 and 418 abutting portion 420 are reinforced to contain theload of fill material when portion 420 is evacuated.

The associated electronic controls for the medical device are includedon portion 406, which is adapted to be slid out between portions 412 and414. While each of sections 404, 420 and 416 are preferably coupledtogether, they could be separately removable. In addition rollers orother slide assisting means are preferably provided under the removablesections so that the removable section of pod 103 a can easily bedecoupled and removed and replaced.

In addition provisions can be made to stop the flow of fill materialfrom the roof sections above portion 420 as the removable portion of pod103 a are removed. Turning now to FIGS. 12 and 13, pod 109 a, which is amodified version of pod 109, is depicted. Pod 109 a is substantiallyidentical to pod 109 save the centralized trapezoidal portion 450 whichis located to cover portion 420 in pod 103 a. Portion 450 is constructedof reinforced steel and has access ports to both fill and evacuateportion 450 of radiation fill material when removable section of pod 103a is to be removed. The lateral sides of portion 450 are constructed tocontain the load of the remaining radiation fill material in pod 109 afrom falling into portion 420 during medical device removal andswapping.

As can be appreciated by those of skill in the art when provided withthe present disclosure, the modular structure can be formed bysequentially placing and connecting the pods in proper alignment. Tofacilitate construction and alignment of the pods, adjacent pods can beprovided with quick locking and/or aligning devices and/or the pods canbe connected in any conventional fashion. For example adjacent sides oftwo pods can be provided with a post and receiving hole to align withthe respective post or receiving hole of the adjacent pod.

Turning now to FIG. 15A, a representative connection between the lowerrails 92 of a pair of footprint pods is illustrated. Alignment post 515of rail 92 a is received in the hole 516 of rail 92 b, and the two railsare secured by a bolt and locking washer assembly 530.

Turning to FIG. 15B, a representative connection between the verticalposts 94 at the corners of adjacent pods is illustrated. Post 94 b,including wall section 511 b, is connected with long bolt assembly 531to post 94 a, including adjacent wall section 511 a.

Turning now to FIG. 15C, an interior wall connection between adjacentpods is illustrated. Adjoining rails 96, or equivalently wall supports202, are connected by bolt assembly 532. One or more of the rails 96 caninclude a reinforced wall portions, such as wall 303. (See FIG. 7)

As shown in FIG. 1 SD, the rails 96 a and b (of adjacent pods) holdingceiling panels 540 a and b are connected in similar fashion as areadjacent interior wall portions. The ceiling panels 540 a and 540 bcould be the ceiling over the central treatment area 50, or the ceilingpanels could serve as the roof over the entire structure, as would bethe case in the respective connection between pods 106 and 107.

Turning to FIG. 15E, a representative connection between an interiorportion of pod 101 with the door gusset 540 of pod 102 is illustrated. Arepresentative wall panel 510, reinforced with support 202, is securedto a portion of the door gusset 540 with a standard bolt assembly.

Turning now to FIG. 15F, a representative connection between the ends ofa roof pod with the outside walls of pods 101 and 105 is depicted. Theupper frame rail 96 from the outside wall 510 of a footprint podreceives a bolt assembly holding the lower beam 92 forming the bottom ofa roof pod, such as pod 107. A spacer 550 can also be included betweenthe pods.

Turning now to FIG. 15G, a representative connection between an I-beamin the roof pod and the roof support in the footprint pod is depicted.I-beam 321 (see FIG. 8-8B) is connected through the floor of the roofpod and into a top flat portion of the support 120 (see FIG. 3) with abolt assembly.

In addition while each radiation fill material containing section ofeach of the individual pods can include their own access port or portsfor filling and removing radiation fill material, in one embodiment onlythe roof pods have access ports. In this embodiment the access ports canbe along the top roof section of the roof pods and radiation fillmaterial provided into those roof pods can flow by gravity into theappropriate portions of the footprint pods 101 through 105.

It is also envisioned that the modular structure can be disassembled bysequentially decoupling and removing the pods. For the roof pods, theradiation fill material can be pumped out of or otherwise removed fromthe containers prior to lifting the pods. The footprint pods, sincethere is no floor in the barrier sections, can be lifted by their endswith the filler material being left behind. It may be necessary to rapthe sides of the pods as they are being lifted to assure that the fillerdoes not stick to the inside of the pods. Alternatively, the fillermaterial can be pumped out of the footprint pods prior to their removal.

While in the preferred embodiment, the radiation shielding fillermaterial is sand or another solid flowable or granular radiationadsorbent material, other types of filler material can be used. Examplesinclude, without limitation, silica, dirt, lead, lead shot, steel, scrappieces (such as metal punch outs), and various combinations or mixturesof the above. Where the barrier region is made substantially fluid tightsuch as by providing a bladder and/or caulking throughout the barrierregion once the pods are constructed, the filler material can be aliquid (such as water) or a slurry (such as a flowable fill concrete).Furthermore, it is contemplated that the specific type of shieldingmaterial and the physical dimension of the barrier region can betogether varied and selected to provide the necessary radiationshielding based on a particular application and a particular radiationsource. As discussed throughout, the density of the fill material willdetermine at least to some extent the load on the walls of the barrier,and the walls can be constructed and/or reinforced as appropriate basedon the expected load and any applicable building codes or constructiontechniques.

While the structure illustrated herein is constructed substantiallyentirely from free-standing pods, it is contemplated that the pods couldonly form a portion of a treatment facility. For example pods 102 and/or103 could be provided wherein the remainder of the structure and/or thebarrier (i.e. that formed in the illustrated embodiment by the remainderof the pods) could be constructed by any building technique now known orhereafter developed. For example portions of the structure could betransported as preformed but collapsed portions that would be assembledand arranged around the placed pods.

It is to be understood that the invention is not limited to the specificfeatures shown and described, since the means herein disclosed comprisepreferred forms of putting the invention into effect. The invention is,therefore, claimed in any of its forms or modifications within theproper scope of the appended claims appropriately interpreted inaccordance with the doctrine of equivalents.

1. A method comprising: providing a transportable module for forming a structure, the module comprising: a free standing rigid frame structure and a pair of reinforced rigid walls mounted to and maintained in a predetermined spaced apart opposing relationship by the rigid frame structure so as to define a void space between the walls, wherein at least a portion of the void space between the walls does not contain a ceiling or a floor; and then lifting the module by its ends; and then placing the module on a supporting surface with a major axis of the module horizontal; and then filling the void space with a radiation shielding granular fill, the granular fill contacting the supporting surface to form a substantially continuous lateral barrier to protect persons on a first side of the barrier from radiation emitted by a piece of radiation emitting equipment on a second opposing side of the barrier.
 2. The method of claim 1 further comprising: resisting lateral forces acting from inside the channel to force the walls apart with rigid supports connected in the space between the walls.
 3. The method of claim 1 wherein a plurality of modules are provided.
 4. The method of claim 1 wherein the walls comprise steel.
 5. The method of claim 1 wherein the module has a length substantially greater than its height.
 6. The method of claim 1 wherein the supporting surface for the module is provided by a concrete foundation.
 7. The method of claim 1 wherein a plurality of modules are coupled together with void spaces in adjacent modules substantially aligned, the aligned void spaced forming a perimeter substantially surrounding a central area.
 8. The method of claim 7 wherein a piece of therapeutic radiation emitting equipment is provided on the second side of the barrier, whereby humans in the central area may be treated with the radiation emitting equipment while humans outside the central area are protected.
 9. The method of claim 1 further comprising providing the module with a support frame for the piece of radiation emitting equipment.
 10. A method of constructing a radiation shielding structure comprising: providing a plurality of transportable modules, the modules each comprising: a free standing rigid frame structure and a pair of reinforced rigid walls mounted to and maintained in a predetermined spaced apart opposing relationship by the rigid frame structure so as to define a void space between the walls, wherein at least a portion of the void space does not contain a lower bound, lifting and then placing the modules on a first supporting surface such that the first supporting surface forms the lower bound of the void spaces, a major axis of the modules is horizontal, and void spaces of adjacent modules are substantially aligned with each other, wherein the aligned void spaces form a perimeter substantially surrounding a central area; and after placing the modules on the first supporting surface, filling the aligned void spaces with a radiation shielding material to form a substantially continuous radiation shielding barrier around the central area.
 11. The method of claim 10 further comprising: providing a reinforced second supporting surface over the central area; and covering the reinforced second supporting surface with the radiation shielding material to form a radiation shielding barrier over the central area.
 12. The method of claim 11 wherein the radiation shielding material is flowable and a portion of the radiation shielding material placed on the reinforced second supporting surface is allowed to flow into the void space between the walls.
 13. The method of claim 11 wherein the reinforced second supporting surface is formed by placing a plurality of free standing modules over the central area.
 14. The method of claim 11 further comprising placing a piece of radiation emitting equipment in the central area, whereby humans in the central area may be treated with therapeutic radiation doses with the radiation emitting equipment while humans outside the central area are protected.
 15. The method of claim 10 wherein at least one of the modules is lifted by its ends.
 16. The method of claim 15 wherein each of the modules are lifted by their respective ends.
 17. The method of claim 10 wherein the modules are lifted with a crane. 